A 2007 study in the journal Dental Traumotology1 measured neurocognitive function in two groups of athletes: those who sustained a concussion while wearing a mouth guard and those who were not wearing a mouth guard when they sustained a concussion. Researchers found no difference in brain function between the two groups - meaning that mouth guards did not prevent a loss of brain function after concussive injury.

A 1987 study of rugby players published in the British Journal of Sports Medicine2 showed no statistical difference in the rates of concussion between rugby players wearing mouth guards and those not wearing mouth guards.

More recent studies have claimed that custom-made, form-fitting, special individualized mouth guards called custom mandibular orthotics (CMOs) may decrease the risk of concussion. However, the results are unclear. Any effects of CMOs and other mouth guards on concussions remains unknown.

Still worth wearing

As with helmets, however, it is well established that mouth guards reduce the risk of facial bone fractures and dental injuries. Therefore, all athletes participating in sports that require the use of a mouth guard should wear an undamaged, properly fitting mouth guard while they are playing.